Locking device



Oct. 11, 1966 N. ALFoNso LOCKING DEVICE Filed OO-t. 9, 1964 5s s2 s2 24 I6 42 O 3 E Q m mm QM fl 0 s 0 u I I w INVENTOR.

Nick J. Alfonso UIIIIIIIIII United States Patent C) 3,277,729 LOCKING DEVICE Nick I. Alfonso, Chicago, Ill., assignor to Motorola, Inc., Franklin Park, 11]., a corporation of Illinois Filed Oct. 9, 1964, Ser. No. 402,703 6 Claims. (Cl. 7410.33)

This invention relates to pushbutton tuning mechanisms for radio receivers and more particularly to an improved locking device for use in presetting an adjustable pushbutton structure to permit repeated selection of a given station.

In radio tuners it is common to provide an adjustable cam member supported on a slidably mounted plunger rod. The cam member engages a treadle bar structure, including a pair of parallel members mounted on a rotatable carriage, coupled to tuning elements associated with a resonant circuit. In such mechanisms the cam member is fixed at a certain angle with respect to its supporting plunger rod so that as the rod is moved with respect to the parallel members, the cam member engages the parallel treadle bar members and brings them into alignment with the surface of the cam member. This sets the carriage and the resonant circuits of the radio to the proper adjustment for reception of a particular station.

Devices of this type which have heretofore been available have the disadvantage in that they require several components. Furthermore, because assembly time is proportional to the number of components, labor costs for assembly are relatively high.

It is an object of the invention to decrease the number of parts required to provide a suitable locking device for presettable pushbutton tuners thereby reducing the material cost.

It is another object of the invention to provide a locking device for a presettable pushbutton tuner that is simple to assemble with a resultant reduction in assembly time followed by reduced labor costs.

A feature of the invention is the provision, in a pushbutton slide mechanism, of an integral U-shaped plunger rod slidably and removably engaged with an actuating bar to clamp a cam member rotatably mounted on the plunger rod in a fixed position with respect to the actuating bar.

Another feature of the invention is the integral U- shaped portion doubled upon itself forming the plunger rod such that the resulting hairpin bend imparts resilience to the locking lever portion of the plunger rod so that when the pushbutton slide mechanism is in the unlocked position the resilience of the locking lever will lift the lever clear of the cam member permitting it to rotate with respect to the actuating bar.

In the drawing:

FIG. 1 is a plan view of the pushbutton assembly of the invention in locked position;

FIG. 2 is a side elevation thereof;

FIG. 3 is a half section thereof;

FIG. 4 is a half section thereof in unlocked position;

FIG. 5 is a perspective view of a part of the assembly; and

FIG. 6 is a view taken along plane 66 of FIG. 5.

This invention provides a mechanism for locking and releasing a cam member on a plunger rod in a pushbutton control mechanism such as the tuning apparatus for a radio receiver. The plunger assembly is of the push-tolock type. A slidable actuating bar is operated by the pushbutton. The plunger rod is slidably and removably attached to the actuating bar.

In this particular form of the invention the plunger rod is U-shaped consisting of two variably spaced arms integrally joined at a juncture forming a hairpin bend. The arms extend in unequal length from the juncture.

3,277,729 Patented Oct. 11, 1966 "ice The longer arm has a T lug on it which fits into a slot in the actuating bar, thereby slidably attaching it to the bar. The cam which is to be clamped in relation to the actuating bar, is rotatably held to this longer arm by a projection thereon. The shorter arm forms a locking lever that actually clamps the cam to the longer arm in fixed relationship to the actuating bar. This locking lever has a cross-sectional area which is reduced as compared to the area of the juncture of the two arms of the plunger rod. This reduced area combines with the effect of the hairpin bend to impart resilience to the locking lever.

In operation there is a hooked shaped portion integral with the actuating bar. This hooked shaped portion encircles the locking lever. There is a raised or arcuate portion on the locking lever. When the actuating bar is moved in one direction with relation to the plunger rod, the hook shaped portion contacts the arcuate portion of the locking lever moving it against the cam and clamping it to the plunger rod in a fixed relationship with the actuating bar, and when the actuating bar is moved in the opposite direction the hooked shaped portion clears the arcuate portion thereby permitting the resilience of the locking lever to unclamp the cam.

Referring to FIG. 1, pushbutton 10 is shown protruding partially through the faceplate of a radio receiver, a portion of which is represented at 12. Slidable actuating bar 14 is fixed to, and operable by, pushbutton 10. The actuating bar 14 in turn operates plunger rod 20 which controls the tuning mechanism of the radio receiver.

As may be seen more clearly in FIG. 2, actuating bar 14 has a guide slot 16 formed therein. T lug 18, which is part of plunger rod 20, is removably fitted into guide slot 16 and is slidable therein. Plunger rod 20 has a projecting. pivot portion 22 extending from one side. Cam member 24, which is of generally semicircular shape, has an opening for receiving pivot portion 22 to provide a pivotal mounting of the cam member 24 with respect to plunger rod 20.

Referring to FIG. 5, it can be seen that the plunger rod 20 is U-shaped, consisting of two variably spaced arms 26 and 28 integrally joined at a juncture 30 forming a hairpin bend 32. The arms 26 and 28 extend in unequal lengths. The longer arm 26 of the plunger rod 20 carries the T lug 18 and supports the cam member 24. The shorter arm 28 forms a locking lever that actually clamps the cam 24 to the arm 26 in a fixed relationship with the actuating bar 14 as will be explained in greater detail subsequently. This locking lever 28 has a crosssectional area 34 which is reduced as compared to the area 36 of the juncture 30 of the arms 26 and 28 as shown in FIG. 6. This reduced area 34 combines with the eilect of the hairpin bend 32 to impart resilience to the locking lever 28.

There is shown in FIG. 2 one of a plurality of slug tuned coil units 40 which are supported by the chassis of the tuner represented at 42. The unit 40 may include a resonant circuit of the radio receiver as is known to those familiar with the art. The movable slug 44 of the unit 40 is fastened to a slidable portion of carriage 46 by means of screw rod 4 8 and threaded anchor 50. Carriage 46 also includes a treadle structure comprising a pair of parallel bar members 52 mounted on an arm 54 treadable about an axis midway between the bar assembly. Link section 56 connects the slidable portion of carriage 46 to an extension of thearm 54 so that as bars 52 are rotated about their axis, carriage 46- and slug 44 attached thereto are moved to eflFect continuous tuning of the coil units 40. To fix the cam member 24 at a desired angular position, for pushbutton operation of the tuning apparatus, the carriage 46 is first adjusted by suitable manual tuning means to'a desired setting with the bars 52 in a position characteristic of that setting. The cam member 24 is then unlocked by drawing pushbutton outwardly from the faceplate of the receiver 12 thereby drawing with it act uating bar 14. Plunger rod remains in a fixed relationship to the movement of the actuating bar 14 relative to the chassis 42 due to the'butt portion 60 engaging chassis 42 and is' further restricted in motion relative to the actuating bar 14, only, by the length of slot 16 in which -T lug18 fits to slidably connect the actuating bar 14 and the push rod 20. Conversely the cam member 24 is locked by pushing the push-button 16 inwardly toward the faceplate of receiver 12. This causes joint motion of the plunger rod 20 and the actuating bar 14 until the diametric edge of cam member 24, which is free to rotate on the plunger rod 20, cont-acts the parallel bar members 52 and assumes the angle of these bars. The bars prohibit fur- .thcr rotation of the cam member 24 with the result that the plunger rod 20 is held in a fixed position while the actuating bar 14 continues to move relative to plunger rod 20 until the slot 16' in actuating bar 14 reaches the T lug on arm 26 of plunger rod 20'. At this point the actuating bar 14 is no longer free to move relative to the plunger rod 20 and the cam 24 is held in a clamped posi tion. The spring 58 then biases the pushbutton assembly back to its normal operating position.

Thereafter, whenever desired, tuning slug 44 may be returned to the preset position by depressing pushbutton 10 and hence the entire assembly against spring 58 causing cam member 24 to bring parallel bars 52 into alignment with the diametric surface thereof.

The clamping action of locking lever 28 can be more easily understood by referring to FIGS. 3 and 4. The book shaped portion- 62 integral with the actuating bar 14 encircles the locking lever 28. There is a raised or arcu'ate portion 64 on the locking lever. When the actuating bar 14 is moved in the direction to clamp the cam member 24 in a fixed position as previously discussed, the hook shaped portion 62 engages the arcuate portion 64 of the locking lever 28 and rides over the top of the raised portion thereby pressing the locking lever against the cam member 24 and clamping it in a fixed position to arm 26 of plunger rod 20. In a similar manner to unclamp cam member 24 actuating bar -14 is moved in the opposite direction. The hook shaped portion 62 then rides down, off of the arcuate portion 64, and is disengaged therefrom. The resilience of locking lever 28 then springs the lever clear of cam member 24 thereby unclamping it.

Since there are relatively few parts including no springs the assembly of the slide mechanism is simple. Cam member 24 is placed on arm 26 and held in place by pivot portion .22.- The operation is completed by inserting T lugs 18 into guide slot 16 of the slidable actuating bar 14. It should be noted that this method of attaching the, plunger rod and actuating bar is not critical to the invention and other means known in the art such as using a rivet and anti-rattle spring will work equally as well. Plunger rod 20 is then pivoted into hook shaped locking portion 62 through the opening therein thereby slidably connecting the plunger rod 20 and the actuating bar 14. The pushbutton slide mechanism is then ready for installation.

The invention provides, therefore, a locking mechanism for locking a cam member on a pushbutton plunger rod in a desired angular position which locking mechanism contains few component parts and is therefore relatively simple to assemble and inexpensive to manufacture.

I claim:

- 1. A pushbut-ton slide mechanism, including in combination, a slidable actuating bar adapted to be manually operated, a plunger rod slidably mounted to said actuat ing bar, said plunger rod including an integral U-shaped portion doubled upon itself to form a pair of resilient arms with varied spacing therebetween, a cam pivotally mounted on said plunger rod in a position to be clamped by closure of said arms of said U-shaped portion, said actuating bar including means for energizing and closing said integral U-shaped portion upon relative longitudinal movement of said bar and said rod in one direction and for releasing said U-shaped portion to unclamp said cam upon relative longitudinal movement thereof in the opposite direction.

2. A pushbutton slide mechanism, including in combination, a slidable actuating bar adapted to be manually operated, a plunger rod slidably mounted to said actuating bar, said plunger rod including an integral U-shaped portion doubled upon itself into two variably spaced arms integrally joined at a juncture forming a hairpin bend, said hairpin bend imparting resilience to said arms, a cam pivotally mounted on said plunger rod in a position to be clamped by closure of said arms of said U-shaped portion, said actuating arm including means for engaging and closing said integral U-shaped portion upon relative longitudinal movement of said bar in said rod in one direction and for releasing said U-shaped portion to unclamp said cam upon relative longitudinal movement thereof in the opposite direction.

3. A pushbutton slide mechanism, including in combination, a slidable actuating bar adapted to be manually operated, a U-shaped plunger rod slidably mounted to said actuating bar consisting of two variably shaped arms integrally joined at a juncture forming a hairpin bend, said arms extending in unequal lengths from said hairpin bend, the shorter of said arms forming a locking lever, said locking lever having a reduced cross-section as compared to said juncture, said reduced cross-section of said locking lever imparting resilience to said locking lever, a cam pivotally mounted on the longer of said arms in a position to be clamped by closure of said arms, said actuating bar including means for engaging and closing said arms upon relative longitudinal movement of said bar in said rod in one direction and for releasing said .U- shaped portion to unclamp said cam upon relatively longitudinal movement thereof in the opposite direction.

4. A pushbutton slide mechanism for use in a presettable pushbutton tuner for a radio receiver, including in combination, a slidable actuating bar adapted to be manually operated, a U-shaped plunger rod slidably mounted to said actuating bar consisting of two variable spaced arms integrally joined at a juncture forming a hairpin bend, said arms extending in unequal lengths from said hairpin bend, the shorter of said arms forming a locking lever, said locking lever having a reduced cross-section as compared to said juncture, a combination of said hairpin bend and said reduced cross-section of said locking bar imparting resilience to said locking lever, a cam pivotally mounted on the longer of said arms, in a position to be clamped by closure of said arms, said actuating bar including means for engaging and closing said arms upon relative longitudinal movement of said bar and said rod in one direction and for releasing said U- shaped portion to unclamp said cam upon relative longitudinal movement thereof in the opposite direction.

5. A pu'shbutton slide mechanism for use in a presettable pushbutton tuner for a radio receiver, including in combination, a slidable actuating bar adapted to be manually operated, a U-shaped plunger rod slidably mounted to said actuating bar consisting of two variable spaced anms integrally joined at a juncture forming a hairpin bend, said arms extending in unequal lengths from said hairpin bend, the shorter of said arms forming a resilient locking member, a cam pivotally mounted on the longer arm, said locking lever having an arcuate portion of increased spacing between the U-shaped arms of said plunger rod, a hook shaped locking portion integral with said actuating bar and encircling said locking lever so that upon movement of said actuating bar in one direction said hook shaped locking portion of said actuating bar engages said arcuate portion of said locking lever thereby clamping said cam member in a fixed position with respect to said actuating bar, and movement of said actuating bar in the closing direction causes said hook shaped locking portion to disengage from arcuate portion of said locking bar whereby said resilience of said locking lever springs said locking lever clear of said cam thereby unclamping said cam with respect to said actuating bar.

6. A pushbutton slide mechanism for use in a presettable pushbutton tuner for a radio receiver having tuning elements including in combination, a slidable actuating bar adapted to be manually operated and having a guide slot therein, a U-shaped plunger rod consisting of two variably spaced arms integrally joined at a juncture forming a hairpin bend, said arms extending in unequal lengths from said hairpin bend, the longer of said arms having a T lug thereon slidable in said guide slot of said actuating bar and removable there-from, the shorter of said arms forming a locking lever, said locking lever having a reduced cross-section as compared to said juncture, a combination of said hairpin bend and said reduced crosssection of said locking lever imparting resilience to said locking lever, a cam pivotally mounted on said longer arm, said cam being used to position one of said tuning elements within the radio receiver, said locking lever having an arcuate portion of increased spacing between the U-shaped arms of said plunger rod, a hook shaped locking portion integral with said actuating bar and encircling said locking lever so that upon movement of said actuating bar in one direction said hook shaped locking portion of said actuating bar engages said arcuate portion of said locking lever thereby clamping said cam member in a fixed position with respect to said actuating bar and movement of said actuating bar in the opposing direc tion causes said hook shaped locking portion to disengage from arcuate portion of said locking bar Whereby said resilience of said locking lever springs said locking lever clear of said cam thereby unclamping said cam with respect to said actuating bar.

References Cited by the Examiner UNITED STATES PATENTS 3,195,359 6/1965 Clark 74-1033 References Cited by the Applicant UNITED STATES PATENTS 2,800,027 7/ 1957 Schwarz.

2,930,241 3/ 1960 Roback.

3,086,401 4/ 1963 Horton.

FOREIGN PATENTS 742,939 1/1956 Great Britain.

MILTON KAUFMAN, Primary Examiner. 

1. A PUSHBUTTON SLIDE MECHANISM, INCLUDING IN COMBINATION, A SLIDABLE ACTUATING BAR ADAPTED TO BE MANUALLY OPERATED, A PLUNGER ROD SLIDABLY MOUNTED TO SAID ACTUATING BAR, SAID PLUNGER ROD INCLUDING AN INTEGRAL U-SHAPED PORTION DOUBLED UPON ITSELF TO FORM A PAIR OF RESILIENT ARMS WITH VARIED SPACING THEREBETWEEN, A CAM PIVOTALLY MOUNTED ON SAID PLUNGER ROD IN A POSITION TO BE CLAMPED BY CLOSURE OF SAID ARMS OF SAID U-SHAPED PORTION, SAID ACTUATING BAR INCLUDING MEANS FOR ENERGIZING AND CLOSING SAID INTEGRAL U-SHAPED PORTION UPON RELATIVE LONGITUDINAL 